[ARM] S3C24XX: Fix spi-bus configuration build errors

The commit ec976d6e
removed a number of gpio definitions from <mach/hardware.h>
but misssed updating these two files:

Fix the following build errors by including <linux/gpio.h>:
arch/arm/plat-s3c24xx/spi-bus1-gpg5_6_7.c: In function 's3c24xx_spi_gpiocfg_bus1_gpg5_6_7':
arch/arm/plat-s3c24xx/spi-bus1-gpg5_6_7.c:25: error: implicit declaration of function 's3c2410_gpio_cfgpin'
arch/arm/plat-s3c24xx/spi-bus1-gpg5_6_7.c:28: error: implicit declaration of function 's3c2410_gpio_pullup'
arch/arm/plat-s3c24xx/spi-bus0-gpe11_12_13.c: In function 's3c24xx_spi_gpiocfg_bus0_gpe11_12_13':
arch/arm/plat-s3c24xx/spi-bus0-gpe11_12_13.c:25: error: implicit declaration of function 's3c2410_gpio_cfgpin'
arch/arm/plat-s3c24xx/spi-bus0-gpe11_12_13.c:28: error: implicit declaration of function 's3c2410_gpio_pullup'

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>